1. Field of the Present Invention
The invention relates to a velocity calculating apparatus, a velocity calculating method, a navigation apparatus, and a mobile phone with a navigation function, and more particularly, to a portable type navigation apparatus.
2. Description of the Related Art
In the related art, a navigation apparatus is configured to receive positioning signals (hereinafter, referred to as GPS signals) from a plurality of GPS (global positioning system) satellites and to calculate a current position of a movable object (for example, a vehicle, or the like) based on the GPS signals.
However, in such a navigation apparatus, in the case where a vehicle in which the navigation apparatus is installed enters into, for example, a tunnel, an underground parking lot, or the like, the GPS signals may not be received from the GPS satellites, so that the current position of the vehicle may not be calculated based on the GPS signals.
Therefore, among the navigation apparatuses, there is a navigation apparatus which calculates the current position even in the case where the GPS signals may not be received. In the navigation apparatus, at the time of cornering, a velocity in a moving direction is calculated based on an acceleration in the horizontal direction perpendicular to the moving direction of the vehicle and an angular velocity around the vertical axis perpendicular to the moving direction, and the current position is calculated based on the velocity in the moving direction (for example, refer to Japanese Unexamined Patent Application Publication No. 2008-76389).